The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Debit card brings bitcoin to back pocket

A Melbourne company unveiled on Thursday the country's first bitcoin debit card, which will allow users to spend the digital currency at ATMs and eftpos terminals.

Users can pre-load the card with bitcoin, which is converted to Australian dollars.

The company will exchange bitcoin at a rate based on the day's global aggregate. At present, that's about $500 a bitcoin.

The chief executive of bitcoin exchange CoinJar, Asher Tan, said the Swipe card was designed to demystify the currency.

"We simply wanted to make it easier for our customers to spend their bitcoin," he said.

The currency, which was invented in 2009, is still viewed by many as the preserve of technologists and the digital elite.

Reports of black market activities and hacking attacks, including one that fatally wounded the world's biggest exchange, Mt Gox, this year, have also dented bitcoin's reputation.

But Australian entrepreneurs are determined to bring it into the mainstream.

An important step came in April with the Sydney launch of the country's first ATM capable of converting cash into bitcoin and back again.

A second and a third have since popped up in Melbourne and Canberra, and more are planned for other capital cities.

In the past 12 months, Mr Tan said his company had processed more than $50 million worth of bitcoin transactions for about 30,000 people and businesses.

Mr Tan said CoinJar would trial the cards with 100 existing customers.

The company will charge a one per cent commission when the card is loaded.

The launch comes a month after the Australian Taxation Office dealt a blow to companies such as CoinJar by announcing it would treat bitcoin as property rather than currency, making it subject to capital gains tax.

It's believed about seven per cent of the 13.2 million bitcoins in existence are owned by Australians.